A triterpenic acid such as ursolic acid has been known to have various physiological effects such as antioxidative effect, anti-inflammatory effect, and melanin production suppression effect, and technologies to blend the triterpenic acid into a preparation for external application for skin such as cosmetics have been known (see Patent Documents 1, 2, 3, 4, and 5, for example). However, the compounds have insufficient solubility in both an oily ingredient and an aqueous ingredient, and have a problem of precipitation of a triterpenic acid during long-term preservation. Physiological activities of a triterpenic acid may be reduced due to insufficient solubility, resulting in the insufficient physiological effects. Under such circumstances, the solubility of a triterpenic acid in an oily ingredient was improved by, for example, esterifying a triterpenic acid to yield a derivative of the triterpenic acid. However, this method is not considered to be satisfactory for preventing precipitation of a triterpenic acid (see Patent Document 6, for example). That is, there has been required means for improving solubility in a preparation without impairing physiological activities of a triterpenic acid such as ursolic acid that is known to have various physiological activities.
On the other hand, technologies to phosphorylate a compound having hydroxyl groups to obtain a phosphate have been known, and in the cosmetic fields, chemical modifications into phosphate derivatives are performed to stabilize sugars or sugar analogues such as ascorbic acid (see Patent Documents 7 and 8, for example). However, there are no examples of phosphorylation for improving solubility, and a phosphorylated compound of a triterpenic acid is a novel compound that has not been described in documents.
Patent Document 1: JP 08-165231 A
Patent Document 2: JP 08-208424 A
Patent Document 3: JP 01/072265 A1
Patent Document 4: JP 11-012122 A
Patent Document 5: JP 2000-302659 A
Patent Document 6: JP 2004-331593 A
Patent Document 7: JP 11-158197 A
Patent Document 8: JP 2001-354513 A